Recently, liquid crystal display apparatuses (i.e. liquid crystal displays (“LCDs”)) are spreading as display apparatuses for various electronic equipment such as personal computers, mobile terminals and television displays. Liquid crystal display apparatuses are non-self-luminous display apparatuses, and therefore need to have a planar light source apparatus (hereinafter “light source apparatus”) in addition to a liquid crystal display element. The planar light source apparatus is demanded to provide a wider color reproduction area, reduced activation time and higher efficiency, and furthermore is demanded to be made thinner. Therefore, a planar light source apparatus (i.e. laser backlight) using a laser light source is gaining popularity.
A laser light generated in a laser light source is a spot light with strong directivity. Accordingly, in case where a laser light source is used in a planar light source apparatus, a technique of converting this laser light, which is a spot light, into a planar light, is required. For example, Patent Document 1 and Patent Document 2 disclose a planar light source apparatus using a laser light source.
FIG. 1 is a perspective view showing a configuration of the planar light source apparatus disclosed in Patent Document 1.
Planar light source apparatus 10 shown in FIG. 1 has laser light source 20, reflecting member 30 and deflecting member 40. Reflecting member 30 has film 33 arranging a plurality of reflection-type volume holograms in one plane of base material 32, and deflects laser light 21 incident on this plane at a high angle of incidence, toward a direction virtually vertical to the end surface of deflecting member 40. By this means, reflecting member 30 widens a laser light in one dimension, converts the laser light into linear lights, and allows the converted linear lights to be incident on deflecting member 40. Deflecting member 40 allows the incident light to propagate inside by light guiding body 42, to deflect on a plurality of half mirrors 43 and to be emitted from portions of the main surface. Thus, planar light source apparatus 10 can generate a planar light from a laser light source.
FIG. 2 is a perspective view showing a configuration of a planar light source apparatus disclosed in Patent Document 2.
Planar light source apparatus 50 shown in FIG. 2 has laser light source 60, reflecting part 70 and light guiding plate 80, Reflecting part 70 has a plurality of triangular prism shapes 71 in one plane, and deflects a laser light incident diagonally on this is plane at a high angle of incidence, in a direction virtually vertical to the end surface of light guiding plate 80. By this means, reflecting part 70 widens a laser light in one dimension, converts the light into linear lights and allows the converted linear lights to be incident on light guiding plate 80. Light guiding plate 80 deflects the incident light by a plurality of grooves 81 provided in the main surface of light guiding plate 80 and emits the lights from portions of its main surface. In this way, planar light source apparatus 50 can generate a planar light from a laser light source.    Patent Document 1: Japanese Patent Application Laid-Open No. 2002-169480    Patent Document 2: Japanese Patent Application Laid-Open No. 2001-345008